Regulatory - Additional Information (Detail)														1 Months Ended						12 Months Ended
	Jan. 31, 2027 USD ($)	Jan. 31, 2026 USD ($)	Feb. 04, 2025 USD ($)	Jan. 31, 2025 USD ($)	Dec. 03, 2024	Oct. 09, 2024 Customer	Jun. 13, 2024 USD ($)	Nov. 09, 2023 USD ($)	Jan. 23, 2023 USD ($)	Jul. 01, 2022 USD ($)	Aug. 06, 2021 USD ($)	Nov. 19, 2020 USD ($)	Oct. 31, 2013 USD ($)	Jan. 31, 2024 USD ($)	Sep. 30, 2023 USD ($)	Jan. 31, 2023 USD ($)	Nov. 30, 2022 USD ($)	Sep. 30, 2022 USD ($)	Jan. 31, 2022 USD ($)	May 31, 2025 USD ($)	Dec. 31, 2024 USD ($) Unit	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Sep. 26, 2024 Customer
Public Utilities General Disclosures [Line Items]
Base rate adjustment amount										$ 10,000,000
Utility plant, at original costs																					$ 14,433,000,000	$ 13,655,000,000
Accumulated depreciation																					$ 3,348,000,000	3,443,000,000
Number of units applied for recovery | Unit																					3
Adjustment to fuel and capacity charges recovery																			$ 169,000,000
Adjustments to fuel charges recovery									$ 518,000,000
Adjustments to fuel charges recovery projected reduction									$ 170,000,000
Storm restoration preparation costs																					$ 377,000,000
PGS and OPC [Member]
Public Utilities General Disclosures [Line Items]
Increase in revenue												$ 34,000,000
Accumulated depreciation												34,000,000
Increase in annual base rate												58,000,000
Peoples Gas [Member]
Public Utilities General Disclosures [Line Items]
Accumulated depreciation reversed amount																						20,000,000	$ 14,000,000
Hurricane Ian [Member]
Public Utilities General Disclosures [Line Items]
Storm Reserve Expected to Charge																		$ 121,000,000
Storm restoration costs charged to reserve																$ 10,000,000
Replenishment of balance in reserve													$ 131,000,000								56,000,000
Storm restoration costs							$ 135,000,000											$ 129,000,000
Storm restoration costs balance																						$ 29,000,000
Hurricane Debby [Member]
Public Utilities General Disclosures [Line Items]
Storm restoration costs			$ 466,000,000
Hurricane Nicole [Member]
Public Utilities General Disclosures [Line Items]
Restoration costs																	$ 2,000,000
Hurricane Idalia [Member]
Public Utilities General Disclosures [Line Items]
Storm restoration costs			466,000,000												$ 35,000,000
Hurricane Helene [Member]
Public Utilities General Disclosures [Line Items]
Storm restoration costs charged to reserve																					49,000,000
Number of customers impacted by storm | Customer																								100,000
Storm restoration costs			466,000,000
Hurricane Milton [Member]
Public Utilities General Disclosures [Line Items]
Number of years worst weather event impact on area						100 years
Storm restoration costs charged to reserve																					340,000,000
Number of customers impacted by storm | Customer						600,000
Storm restoration costs			$ 466,000,000
Cast Iron and Bare Steel Replacement Rider [Member] | PGS and OPC [Member]
Public Utilities General Disclosures [Line Items]
Increase in revenue												$ 24,000,000
Scenario Forecast [Member]
Public Utilities General Disclosures [Line Items]
Adjustments to fuel and capacity charges reduction over period																				$ 138,000,000
Settlement Agreement [Member]
Public Utilities General Disclosures [Line Items]
Allowed equity in the capital structure					54.00%						54.00%
Base rate adjustment amount											$ 123,000,000
Increase in revenue											$ 191,000,000
Settlement agreement number of subsequent years adjustments											2 years
Settlement agreement adjustment amount														$ 21,000,000		$ 90,000,000
Basis point increase applicable											0.25%
Additional attainable revenue under settlement agreement											$ 10,000,000
Changes in base rate under agreement											$ 0
Impact of tax reform through reduction in base revenue days											180 days
Settlement Agreement [Member] | US Treasury Bond [Member]
Public Utilities General Disclosures [Line Items]
Calculating period											30 years
Determining period											6 months
Minimum [Member]
Public Utilities General Disclosures [Line Items]
Percentage of ROE										9.25%
Minimum [Member] | PGS and OPC [Member]
Public Utilities General Disclosures [Line Items]
Percentage of ROE												8.90%
Minimum [Member] | Hurricane Ian [Member]
Public Utilities General Disclosures [Line Items]
Storm restoration costs								$ 129,000,000
Minimum [Member] | Settlement Agreement [Member]
Public Utilities General Disclosures [Line Items]
Percentage of ROE											9.00%
Base rate agreement frozen period											Jan. 01, 2022
Minimum [Member] | Settlement Agreement [Member] | Subsequent Event [Member]
Public Utilities General Disclosures [Line Items]
Percentage of ROE				9.50%
Minimum [Member] | Settlement Agreement [Member] | US Treasury Bond [Member]
Public Utilities General Disclosures [Line Items]
ROE revenue basis point on yield rate											0.50%
Maximum [Member]
Public Utilities General Disclosures [Line Items]
Percentage of ROE										11.25%
Maximum [Member] | PGS and OPC [Member]
Public Utilities General Disclosures [Line Items]
Percentage of ROE												11.00%
Maximum [Member] | Hurricane Ian [Member]
Public Utilities General Disclosures [Line Items]
Storm restoration costs								$ 134,000,000
Maximum [Member] | Settlement Agreement [Member]
Public Utilities General Disclosures [Line Items]
Percentage of ROE											11.00%
Base rate agreement frozen period											Dec. 31, 2024
Maximum [Member] | Settlement Agreement [Member] | Subsequent Event [Member]
Public Utilities General Disclosures [Line Items]
Percentage of ROE				11.50%
Mid Point [Member]
Public Utilities General Disclosures [Line Items]
Percentage of ROE										10.20%
Mid Point [Member] | PGS and OPC [Member]
Public Utilities General Disclosures [Line Items]
Percentage of ROE												9.90%
Mid Point [Member] | Settlement Agreement [Member]
Public Utilities General Disclosures [Line Items]
Percentage of ROE											9.95%
Mid Point [Member] | Settlement Agreement [Member] | Subsequent Event [Member]
Public Utilities General Disclosures [Line Items]
Percentage of ROE				10.50%
Retiring Assets [Member] | Settlement Agreement [Member]
Public Utilities General Disclosures [Line Items]
Cost recovery from settlement agreement											$ 68,000,000
Retiring Coal Generation Units and Meter Assets [Member] | Settlement Agreement [Member]
Public Utilities General Disclosures [Line Items]
Settlement agreement cost recovery period											15 years
Tampa Electric Base Rates, on April 02, 2024 [Member] | Subsequent Event [Member]
Public Utilities General Disclosures [Line Items]
Effect of base rate adjustment on revenue				$ 297,000,000
Tampa Electric Base Rates, on April 02, 2024 [Member] | Scenario Forecast [Member]
Public Utilities General Disclosures [Line Items]
Effect of base rate adjustment on revenue	$ 72,000,000	$ 100,000,000
Tampa Electric Base Rates on August 22, 2024 [Member] | Subsequent Event [Member]
Public Utilities General Disclosures [Line Items]
Effect of base rate adjustment on revenue				288,000,000
Tampa Electric Base Rates on August 22, 2024 [Member] | Scenario Forecast [Member]
Public Utilities General Disclosures [Line Items]
Effect of base rate adjustment on revenue	65,000,000	92,000,000
Tampa Electric Base Rates on August 22, 2024 [Member] | After FPSC Final Order [Member] | Subsequent Event [Member]
Public Utilities General Disclosures [Line Items]
Effect of base rate adjustment on revenue				$ 185,000,000
Tampa Electric Base Rates on August 22, 2024 [Member] | After FPSC Final Order [Member] | Scenario Forecast [Member]
Public Utilities General Disclosures [Line Items]
Effect of base rate adjustment on revenue	$ 9,000,000	$ 87,000,000
Big Bend Modernization Project [Member]
Public Utilities General Disclosures [Line Items]
Energy generation capacity investments																					876,000,000
AFUDC included in energy project investment																					$ 91,000,000
Settlement agreement recovery description																					Tampa Electric’s Settlement Agreement provided recovery for the Big Bend modernization project in two phases. The first phase was a revenue increase to cover the costs of the assets in service during 2022, among other items. The remainder of the project costs was recovered as part of the 2023 subsequent year adjustment.
Big Bend Modernization Project [Member] | Minimum [Member]
Public Utilities General Disclosures [Line Items]
Energy project investment term																					2018
Big Bend Modernization Project [Member] | Maximum [Member]
Public Utilities General Disclosures [Line Items]
Energy project investment term																					2022
Big Bend Coal Generation Assets [Member]
Public Utilities General Disclosures [Line Items]
Settlement agreement cost recovery period																					15 years
Storm Restoration Cost Recovery [Member]
Public Utilities General Disclosures [Line Items]
Minimum cost recovery period																					12 months
Replenishment reserve for recovery of cost																					$ 56,000,000